Typical fire alarm systems include a number of fire detectors positioned throughout a building (and/or campus). Signals from those detectors are monitored by a system controller, such as a fire alarm control panel (“FACP”). The FACP, upon sensing an alarm condition, sends commands to one or more notification appliances to alert occupants in one section of the building, in multiple sections of the building, or in all sections of the building. Notification appliances can output a visual notification, an audible notification, or both. Examples of notification appliances include, but are not limited to strobes, horns, speakers, and the like. Notification appliances are typically connected across common power lines on a notification appliance circuit (“NAC”).
Fire alarm systems NACs may be classified as: (1) including non-addressable notification appliances (“non-addressable NAC”); and (2) including addressable notification appliances (“addressable NAC”). Non-addressable notification appliances do not have an address, and, therefore, the FACP cannot communicate with a particular notification appliance. All of the non-addressable notification appliances on a single circuit are activated at the same time, for example by applying power to the circuit. In the addressable system, on the other hand, each notification appliance has a uniquely assigned address, enabling the FACP to send communications to and receive communications from a particular notification appliance.
Each type of fire alarm system has benefits and drawbacks, such as in terms of installation, configuration, and operation. With regard to installation, the non-addressable alarm system is typically more expensive to install in terms of wiring than an addressable alarm system. The non-addressable alarm system is bound to the particular wiring of the system, e.g. a single loop of wiring or linear wiring with each appliance wired in series, so that the wiring may be supervised for open circuit faults. Also, due to the lack of uniquely assigned addresses, notification appliances need to be wired to the proper NAC in order to be properly activated by the FACP. In contrast, an addressable alarm system may be installed without regard to the particular wiring in a building since each appliance is individually supervised to detect open circuit faults. In this way, the installer may lay the wiring as is most convenient (such as by using “T” taps).
With regard to configuration, the addressable alarm system requires much more manpower than the non-addressable alarm system. For example, configuration of the addressable alarm system requires setting a unique address at each notification appliance (such as through switches or other type of means). As another example, configuration of the addressable alarm system requires entering device identification information (such as a label) for each notification appliance. As still another example, configuration of the addressable alarm system may require grouping of the notification appliances. Unlike non-addressable notification appliances (which are activated by modifying the power to the NAC to which they are connected), addressable notification appliances need not be grouped based on wiring. Instead, the group(s) to which each addressable notification appliance is to be assigned be manually designated so that the FACP can simultaneously turn a group of addressable notification appliances on/off at the proper times. Such a grouping is called a virtual NAC (“VNAC”), with each of the addressable notification appliances in the VNAC being “turned on” by the FACP, preferably using a single group-directed command.
With regard to operation, the addressable alarm system has advantages over the non-addressable alarm system. As merely one example, advanced diagnostics are available in the addressable alarm system that are not available in the non-addressable alarm system. For example, the FACP may send a command to an addressable notification appliance to perform a self-test. The addressed notification appliance may perform the self test, and then report back the results of the test to the FACP.
Even though installation is easier and operation is better using an addressable alarm system, a majority of fire alarm systems are non-addressable because configuring an addressable alarm system is so much more time-consuming and expensive.